check-if-email-exists
Comes with a ⚙️ HTTP backend.
Check if an email address exists without sending any email.https://reacher.email
👉 Live Demo:This is open-source, but I also offer a SaaS solution that has check-if-email-exists
packaged in a nice friendly web interface. If you are interested, find out more at Reacher. If you have any questions, you can contact me at amaury@reacher.email.
Get Started
3 non-SaaS ways to get started with check-if-email-exists
.
Full docs]
1. ⚙️ HTTP backend using Docker (popular method 🥇) [This option allows you to run a HTTP backend using Docker 🐳, on a cloud instance or your own server. Please note that outbound port 25 must be open.
docker run -p 8080:8080 reacherhq/backend:latest
Then send a POST http://localhost:8080/v0/check_email
request with the following body:
{
"to_email": "someone@gmail.com",
"from_email": "my@my-server.com", // (optional) email to use in the `FROM` SMTP command, defaults to "user@example.org"
"hello_name": "my-server.com", // (optional) name to use in the `EHLO` SMTP command, defaults to "localhost"
"proxy": { // (optional) SOCK5 proxy to run the verification through, default is empty
"host": "my-proxy.io",
"port": 1080,
"username": "me", // (optional) Proxy username
"password": "pass" // (optional) Proxy password
},
"smtp_port": 587 // (optional) SMTP port to do the email verification, defaults to 25
}
Full docs]
2. Download the CLI [Note: The CLI binary doesn't connect to any backend, it checks the email directly from your computer.
Head to the releases page and download the binary for your platform.
> $ check_if_email_exists --help
check_if_email_exists 0.9.1
Check if an email address exists without sending an email.
USAGE:
check_if_email_exists [FLAGS] [OPTIONS] [TO_EMAIL]
Check out the dedicated README.md for all options and flags.
Full docs]
3. Programmatic Usage [In your own Rust project, you can add check-if-email-exists
in your Cargo.toml
:
[dependencies]
check-if-email-exists = "0.8"
And use it in your code as follows:
use check_if_email_exists::{check_email, CheckEmailInput, CheckEmailInputProxy};
async fn check() {
// Let's say we want to test the deliverability of someone@gmail.com.
let mut input = CheckEmailInput::new(vec!["someone@gmail.com".into()]);
// Verify this email, using async/await syntax.
let result = check_email(&input).await;
// `result` is a `Vec<CheckEmailOutput>`, where the CheckEmailOutput
// struct contains all information about our email.
println!("{:?}", result);
}
The reference docs are hosted on docs.rs.
✈️ JSON Output
The output will be a JSON with the below format, the fields should be self-explanatory. For someone@gmail.com
(note that it is disabled by Gmail), here's the exact output:
{
"input": "someone@gmail.com",
"is_reachable": "invalid",
"misc": {
"is_disposable": false,
"is_role_account": false
},
"mx": {
"accepts_mail": true,
"records": [
"alt3.gmail-smtp-in.l.google.com.",
"gmail-smtp-in.l.google.com.",
"alt1.gmail-smtp-in.l.google.com.",
"alt4.gmail-smtp-in.l.google.com.",
"alt2.gmail-smtp-in.l.google.com."
]
},
"smtp": {
"can_connect_smtp": true,
"has_full_inbox": false,
"is_catch_all": false,
"is_deliverable": false,
"is_disabled": true
},
"syntax": {
"domain": "gmail.com",
"is_valid_syntax": true,
"username": "someone",
"suggestion": null
}
}
What Does This Tool Check?
Included? | Feature | Description | JSON field |
---|---|---|---|
✅ | Email reachability | How confident are we in sending an email to this address? Can be one of safe , risky , invalid or unknown . |
is_reachable |
✅ | Syntax validation | Is the address syntactically valid? | syntax.is_valid_syntax |
✅ | DNS records validation | Does the domain of the email address have valid MX DNS records? | mx.accepts_mail |
✅ | Disposable email address (DEA) validation | Is the address provided by a known disposable email address provider? | misc.is_disposable |
✅ | SMTP server validation | Can the mail exchanger of the email address domain be contacted successfully? | smtp.can_connect_smtp |
✅ | Email deliverability | Is an email sent to this address deliverable? | smtp.is_deliverable |
✅ | Mailbox disabled | Has this email address been disabled by the email provider? | smtp.is_disabled |
✅ | Full inbox | Is the inbox of this mailbox full? | smtp.has_full_inbox |
✅ | Catch-all address | Is this email address a catch-all address? | smtp.is_catch_all |
✅ | Role account validation | Is the email address a well-known role account? | misc.is_role_account |
✅ | Gravatar Url | The url of the Gravatar email address profile picture | misc.gravatar_url |
🔜 | Free email provider check | Is the email address bound to a known free email provider? | Issue #89 |
🔜 | Syntax validation, provider-specific | According to the syntactic rules of the target mail provider, is the address syntactically valid? | Issue #90 |
🔜 | Honeypot detection | Does email address under test hide a honeypot? | Issue #91 |
🔜 | Have I Been Pwned? | Has this email been compromised in a data breach? | Issue #289 |
🤔 Why?
Many online services (https://hunter.io, https://verify-email.org, https://email-checker.net) offer this service for a paid fee. Here is an open-source alternative to those tools.
License
check-if-email-exists
's source code is provided under a dual license model.
Commercial license
If you want to use check-if-email-exists
to develop commercial sites, tools, and applications, the Commercial License is the appropriate license. With this option, your source code is kept proprietary. Purchase a check-if-email-exists
Commercial License at https://reacher.email/pricing.
Open source license
If you are creating an open-source application under a license compatible with the GNU Affero GPL license v3, you may use check-if-email-exists
under the terms of the AGPL-3.0.
➡️ Read more about Reacher's license.
❓ FAQ
is_reachable: "unknown"
mean?
What does This means that the server does not allow real-time verification of an email right now. It may happen for multiple reasons: your IP is blacklisted, the SMTP port 25 is blocked, the email account is momentarily receiving too many emails (spam protection)... or the email provider simply does not allow real-time verification at all. The details of this "unknown"
case can be found in the smtp.error
and mx.error
fields.
The library hangs/takes a long time/doesn't show anything after 1 minute.
Most ISPs block outgoing SMTP requests through port 25, to prevent spam. check-if-email-exists
needs to have this port open to make a connection to the email's SMTP server, so won't work behind these ISPs, and will instead hang until it times out. There's unfortunately no easy workaround for this problem, see for example this StackOverflow thread. One solution is to rent a Linux cloud server with a static IP and no blocked ports, see for example our Self-Host Guide for which cloud providers open port 25.
To see in detail what the binary is doing behind the scenes, run it in verbose mode with RUST_LOG=debug
to see the logs.
I have another question.
Feel free to check out Reacher's FAQ.
🔨 Build From Source
Build the CLI from source or the HTTP backend from source.